Although the fetal immune system is considered tolerogenic, preterm infants can suffer from severe intestinal inflammation, including necrotizing enterocolitis (NEC). Here, we demonstrate that human fetal intestines predominantly contain tumor necrosis factor-α (TNF-α)+CD4+CD69+ T effector memory (Tem) cells. Single-cell RNA sequencing of fetal intestinal CD4+ T cells showed a T helper 1 phenotype and expression of genes mediating epithelial growth and cell cycling. Organoid co-cultures revealed a dose-dependent, TNF-α-mediated effect of fetal intestinal CD4+ T cells on intestinal stem cell (ISC) development, in which low T cell numbers supported epithelial development, whereas high numbers abrogated ISC proliferation. CD4+ Tem cell frequencies were higher in inflamed intestines from preterm infants with NEC than in healthy infant intestines and showed enhanced TNF signaling. These findings reveal a distinct population of TNF-α-producing CD4+ T cells that promote mucosal development in fetal intestines but can also mediate inflammation upon preterm birth.

To develop an international core outcome set (COS), a minimal collection of outcomes that should be measured and reported in all future clinical trials evaluating treatments of acute simple appendicitis in children.

Between 0.1-3% of injured children who present at a hospital emergency department ultimately die as a result of their injuries. These events are typically reported as unnatural causes of death and may result from either accidental or non-accidental trauma (NAT). Examples of the latter include trauma that is inflicted directly or resulting from neglect. Although consultation with a forensic physician is mandatory for all deceased children, the prevalence of fatal inflicted trauma or neglect among children is currently unclear.

Appendicitis is one of the most common causes of acute abdominal surgery in children. The clinical course of appendicitis ranges from simple to complex appendicitis. The mechanisms underlying the heterogeneity of appendicitis in children remain largely unclear. Dysregulated T cell responses play an important role in several inflammatory diseases of the intestine, but the extend of T cell dysregulation in appendicitis in children is less well known.

The prevalence of inflicted femur fractures in young children varies (1.5-35.2%), but these data are based on small retrospective studies with high heterogeneity. Age and mobility of the child seem to be indicators of inflicted trauma.

Appendicitis is a global disease affecting roughly 1 in every 12 people in the world, with the highest incidence between ages 10 and 19 years. To date, a wide variety of health outcomes have been reported in randomised controlled trials and meta-analyses evaluating treatments for appendicitis. This is especially the case in studies comparing non-operative treatment with operative treatment. A set of standard outcomes, to be reported in all future trials, is needed to allow for adequate comparison and interpretation of clinical trial results and to make data pooling possible. This protocol describes the development of such a global core outcome set (COS) to allow unified reporting of treatment interventions in children with acute uncomplicated appendicitis.

Non-operative treatment of uncomplicated appendicitis in children is gaining ground. Pending definitive evidence regarding its effectiveness, there is a call to evaluate clinical recovery after non-operative treatment. In this study, we analyzed data collected during initial admission of a multicenter prospective cohort in which children, 7-17 year, were treated non-operatively for uncomplicated appendicitis. During admission clinical parameters (pain and gastro-intestinal symptoms), inflammation parameters and sequential abdominal ultrasound were recorded. In total, 45 children were included, 42(93%) were discharged without the need for appendectomy; median [IQR] pain scores on admission were 5 [4-7], decreasing to 2 [0-3] after 1 day of treatment. Initially, 28/42 (67%) reported nausea and 19/42 (45%) vomiting; after 1 day, this was 3/42 (7%) and 1/42 (2%), respectively. White blood cell count declined from a median [IQR] of 12.9 [10.7-16.7] 10E9/L on admission to 7.0 [5.8-9.9] 10E9/L on day 1. Median [IQR] C-reactive protein levels increased from 27.5 [9-69] mg/L on admission to 48 [22-80] mg/L on day 1, declining to 21.5 [11-42] mg/L on day 2. Follow-up ultrasound showed no signs of complicated appendicitis in any of the patients.Conclusion: Clinical symptoms resolved in most children after 1 day of non-operative treatment. This suggests that non-operative treatment is a viable alternative to appendectomy regarding clinical recovery.Trail registration: NCT01356641 What is Known: • Non-operative treatment of uncomplicated appendicitis in children is safe and its use around the world is gaining ground, however high quality evidence from adequately designed randomized trials is still lacking. • Concerns have been raised regarding the potentially prolonged clinical recovery associated with non-operative treatment. What is New: • Most clinical symptoms resolve after 1 day of non-operative treatment in the majority of children.

Accurate differentiation between simple and complex appendicitis is important since differences in treatment exist. This study aimed to assess the accuracy of ultrasonography in differentiating between simple and complex appendicitis.

Currently, accurate biomarkers differentiating simple (phlegmonous) from complex (gangrenous and/or perforated) appendicitis in children are lacking. However, both types may potentially require different treatment strategies, and the search for diagnostic modalities remains warranted. Previously, we demonstrated a distinct microbiota (both an increased bacterial diversity and abundance) in the appendix of children with complex compared to simple appendicitis. From the same cohort of patients we have collected 35 rectal swabs under general anesthesia prior to appendectomy and microbiota analysis was performed by IS-pro, a 16S-23S rDNA-based clinical microbiota profiling technique. Using the obtained IS-profiles, we performed cluster analyses (UPGMA), comparison of diversity (Shannon Diversity Index) and intensity (abundance in relative fluorescence units) on phylum level, and comparison on species level of bacteria between simple and complex appendicitis. Regarding these analyses, we observed no clear differences between simple and complex appendicitis. However, increased similarity of the microbial composition of the appendix and rectal swab was found within children with complex compared to simple appendicitis. Furthermore, PLS-DA regression analysis provided clear visual differentiation between simple and complex appendicitis, but the diagnostic power was low (highest AUC 0.65).   Conclusion: Microbiota analysis of rectal swabs may be viable to differentiate between simple and complex appendicitis prior to surgery as a supervised classification model allowed for discrimination of both types. However, the current diagnostic power was low and further validation studies are needed to assess the value of this method. What is Known: • Simple and complex appendicitis in children may require different treatment strategies, but accurate preoperative biomarkers are lacking. • Clear differentiation can be made between both types in children based upon the microbial composition in the appendix. What is New: • Increased similarity was found between the microbial composition of the appendix and rectal swab within children with complex compared to simple appendicitis. • Using a supervised classification model rectal swabs may be viable to discriminate between simple and complex appendicitis, but the diagnostic power was low.

This study aims to (1) investigate the neuropathology of mild to severe pediatric TBI and (2) elucidate the predictive value of conventional and innovative neuroimaging for functional outcome. Children aged 8-14 years with trauma control (TC) injury (n = 27) were compared to children with mild TBI and risk factors for complicated TBI (mildRF+, n = 20) or moderate/severe TBI (n = 17) at 2.8 years post-injury. Neuroimaging measures included: acute computed tomography (CT), volumetric analysis on post-acute conventional T1-weighted magnetic resonance imaging (MRI) and post-acute diffusion tensor imaging (DTI, analyzed using tract-based spatial statistics and voxel-wise regression). Functional outcome was measured using Common Data Elements for neurocognitive and behavioral functioning. The results show that intracranial pathology on acute CT-scans was more prevalent after moderate/severe TBI (65%) than after mildRF+ TBI (35%; p = .035), while both groups had decreased white matter volume on conventional MRI (ps ≤ .029, ds ≥ -0.74). The moderate/severe TBI group further showed decreased fractional anisotropy (FA) in a widespread cluster affecting all white matter tracts, in which regional associations with neurocognitive functioning were observed (FSIQ, Digit Span and RAVLT Encoding) that consistently involved the corpus callosum. FA had superior predictive value for functional outcome (i.e. intelligence, attention and working memory, encoding in verbal memory and internalizing problems) relative to acute CT-scanning (i.e. internalizing problems) and conventional MRI (no predictive value). We conclude that children with mildRF+ TBI and moderate/severe TBI are at risk of persistent white matter abnormality. Furthermore, DTI has superior predictive value for neurocognitive out-come relative to conventional neuroimaging.

Although appendicitis is rare in young infants, the reported mortality is high. Primary aim of this systematic review was to provide updated insights in the mortality and morbidity (postoperative complications, Clavien-Dindo grades I-IV) of appendicitis in infants ≤3 months of age. Secondary aims comprised the evaluation of patient characteristics, diagnostic work-up, treatment strategies, comorbidity, and factors associated with poor outcome.

Necrotizing enterocolitis (NEC) is the most lethal disease of the gastrointestinal tract of preterm infants. New and existing management strategies need clinical evaluation. Large heterogeneity exists in the selection, measurement, and reporting of outcome measures in NEC intervention studies. This hampers meta-analyses and the development of evidence-based management guidelines. We aim to develop a Core Outcome Set (COS) for NEC that includes the most relevant outcomes for patients and physicians, from moment of diagnosis into adulthood. This COS is designed for use in NEC treatment trials, in infants with confirmed NEC.